: Your computer will warn you about changing file extensions; select Yes to confirm. You can now load this file directly into the Scratch editor. Key Considerations How can I directly modify a .sb3 file? - Discuss Scratch
: Make sure you are looking at the individual files ( project.json and the assets).
For non-technical users or when you’re in a hurry, several free online tools can “convert” ZIP to SB3.
Converting a file to an (Scratch 3.0 project) file is a simple process because an file is essentially a renamed Direct Conversion Method